CREDIT QUALITY ASSESSMENT - Collateral dependent loans individually evaluated for credit loss (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	$ 32,241	$ 20,717
Allowance related to loans evaluated individually	13,101	11,405
Loans individually evaluated for credit loss without an allowance	49,757	77,001
Total individually evaluated collateral dependent loans	81,998	97,718
Total unpaid contractual principal balance	93,276	115,816
Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	28,862	17,419
Loans individually evaluated for credit loss without an allowance	44,726	71,764
Total individually evaluated collateral dependent loans	73,588	89,183
Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	2,806	2,709
Loans individually evaluated for credit loss without an allowance	3,333	3,509
Total individually evaluated collateral dependent loans	6,139	6,218
Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	573	589
Loans individually evaluated for credit loss without an allowance	1,698	1,728
Total individually evaluated collateral dependent loans	2,271	2,317
Commercial real estate: | Commercial investor real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	18,022	5,612
Allowance related to loans evaluated individually	2,988	1,273
Loans individually evaluated for credit loss without an allowance	24,754	39,615
Total individually evaluated collateral dependent loans	42,776	45,227
Total unpaid contractual principal balance	47,547	49,920
Commercial real estate: | Commercial investor real estate | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	17,686	4,913
Loans individually evaluated for credit loss without an allowance	24,754	39,615
Total individually evaluated collateral dependent loans	42,440	44,528
Commercial real estate: | Commercial investor real estate | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	336	699
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	336	699
Commercial real estate: | Commercial investor real estate | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Commercial real estate: | Commercial owner-occupied real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Allowance related to loans evaluated individually	0	0
Loans individually evaluated for credit loss without an allowance	8,316	11,561
Total individually evaluated collateral dependent loans	8,316	11,561
Total unpaid contractual principal balance	10,306	15,309
Commercial real estate: | Commercial owner-occupied real estate | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	6,125	9,315
Total individually evaluated collateral dependent loans	6,125	9,315
Commercial real estate: | Commercial owner-occupied real estate | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	2,191	2,246
Total individually evaluated collateral dependent loans	2,191	2,246
Commercial real estate: | Commercial owner-occupied real estate | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Commercial real estate: | Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	1,446	1,328
Allowance related to loans evaluated individually	603	603
Loans individually evaluated for credit loss without an allowance	13,529	13,716
Total individually evaluated collateral dependent loans	14,975	15,044
Total unpaid contractual principal balance	16,157	16,040
Commercial real estate: | Commercial AD&C | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	1,446	1,328
Loans individually evaluated for credit loss without an allowance	13,529	13,716
Total individually evaluated collateral dependent loans	14,975	15,044
Commercial real estate: | Commercial AD&C | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Commercial real estate: | Commercial AD&C | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Commercial Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	12,773	13,777
Allowance related to loans evaluated individually	9,510	9,529
Loans individually evaluated for credit loss without an allowance	1,058	9,871
Total individually evaluated collateral dependent loans	13,831	23,648
Total unpaid contractual principal balance	16,088	30,958
Commercial Business | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	9,730	11,178
Loans individually evaluated for credit loss without an allowance	318	9,118
Total individually evaluated collateral dependent loans	10,048	20,296
Commercial Business | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	2,470	2,010
Loans individually evaluated for credit loss without an allowance	629	627
Total individually evaluated collateral dependent loans	3,099	2,637
Commercial Business | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	573	589
Loans individually evaluated for credit loss without an allowance	111	126
Total individually evaluated collateral dependent loans	684	715
Residential real estate: | Residential mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Allowance related to loans evaluated individually	0	0
Loans individually evaluated for credit loss without an allowance	1,737	1,874
Total individually evaluated collateral dependent loans	1,737	1,874
Total unpaid contractual principal balance	2,814	3,225
Residential real estate: | Residential mortgage | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Residential real estate: | Residential mortgage | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	150	272
Total individually evaluated collateral dependent loans	150	272
Residential real estate: | Residential mortgage | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	1,587	1,602
Total individually evaluated collateral dependent loans	1,587	1,602
Residential real estate: | Residential construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Allowance related to loans evaluated individually	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Total unpaid contractual principal balance	0	0
Residential real estate: | Residential construction | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Residential real estate: | Residential construction | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Residential real estate: | Residential construction | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Allowance related to loans evaluated individually	0	0
Loans individually evaluated for credit loss without an allowance	363	364
Total individually evaluated collateral dependent loans	363	364
Total unpaid contractual principal balance	364	364
Consumer | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	0	0
Consumer | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	363	364
Total individually evaluated collateral dependent loans	363	364
Consumer | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0	0
Loans individually evaluated for credit loss without an allowance	0	0
Total individually evaluated collateral dependent loans	$ 0	$ 0